Studies will be conducted to explore the mechanism involved in the metabolism of free and esterified sterol by tissue culture cells. The type of sterol synthesized by cells will be established and the interrelationship between sterol content and content of other cellular lipids will be determined. The relationship between cellular sterol flux and synthesis will be studied. The regulation of individual metabolic steps in sterol synthesis will be examined. Bibliographic references: Rothblat, G. H. Cholesteryl ester metabolism in tissue culture cells. I. Accumulation in Fu5AH rat hepatoma cells. Lipids, 9:526-535, 1974; Bates, S.R. and G.H. Rothblat. Regulation of cellular sterol flux and synthesis by human serum lipoproteins. Biochem et Biophys. Acta, 366:38-55, 1974.